Over the last few years, the U.S. has experienced a troubling resurgence of pertussis, also known as whooping cough. During the COVID-19 pandemic, masking and social-distancing dramatically reduced transmission of many respiratory illnesses, and pertussis cases dropped. Unfortunately, since then, pertussis has been on the rise, and this year is no exception. Public-health experts believe the uptick of cases in 2025 is driven by a combination of factors, including waning immunity from vaccines, declining childhood vaccination rates, low adult vaccination rates, improved tracking of outbreaks, and the fact that pertussis is very contagious. Someone with pertussis can be contagious for up to three weeks after coughing begins.
Many people don’t realize the potentially serious implications that pertussis may have for everyone in their family, especially among infants. Before a vaccine was introduced in the late 1940s, pertussis was a leading cause of childhood illness and death in the United States. The vaccine was so effective that the number of cases in the U.S. went from more than a million diagnosed between 1940-1945 (or more than 100,000 annually), to less than 3,000 a year by the 1970s.
We reached out to Professor of Pediatrics at Yale School of Medicine, Marietta Vázquez, MD, FAAP to help us understand more about the rise in pertussis and ways to help prevent it. “Since 2023, a significant increase in reported pertussis outbreaks has been observed,” explained Dr. Vázquez. “Pertussis remains endemic, with epidemic waves every three to five years.” By staying informed, keeping up to date on all recommended immunizations and watching carefully for early symptoms, parents can help protect their infants from severe illness.
Recognizing and Treating Whooping Cough
“The first three or four months of life are the period of greatest risk of mortality from pertussis, with 90 percent of hospitalizations due to pertussis occurring in children under one year of age,” says Dr. Vázquez. This is primarily due to the fact that newborns’ immune systems are still developing, making them highly vulnerable to serious complications from pertussis, like pneumonia and brain disease (encephalopathy). Newborn airways are small, and the mucus and inflammation from pertussis infection can lead to pauses in breathing also known as apnea. According to CDC, about one third of babies younger than one year old who gets sick with pertussis ends up in the hospital.
Pertussis usually begins with cold-like symptoms like a runny or congested nose, low-grade fever and a cough. However, after one or two weeks, symptoms worsen and the coughing becomes more severe, with repeated, violent coughing fits. These fits often result in vomiting or a struggle to breathe that sometimes produces the characteristic “whoop” sound. Infants may not even cough — instead, they might choke, gasp, turn blue or even stop breathing temporarily, because their small airways are blocked. These are signs of a medical emergency.
Early diagnosis and antibiotic treatment can help lessen severity and prevent worsening of the disease. “Any young infant or child with unexplained fever and prolonged cough should seek medical attention,” recommends Dr. Vázquez.
The Importance of the Pertussis Vaccine
Protection against pertussis relies on two primary vaccines. DTaP and Tdap are combination vaccines that protect against Diphtheria, Tetanus, and Pertussis but differ in recommendations by age. DTaP is for infants and children under age 7, while Tdap is for children over age 7, teens, adults, and pregnant individuals as a booster.
To help protect newborns from pertussis, one dose of the Tdap vaccine is recommended during each new pregnancy, regardless of previous vaccination It is recommended that the Tdap vaccine be received between 27 and 36 weeks of pregnancy, ideally within the early part of the third trimester. “By administering the pertussis vaccine during the last stages of pregnancy, the defenses in the pregnant woman increase. These defenses (antibodies) pass through the placenta and protect the newborn until the newborn can receive the first dose of pertussis vaccine according to the vaccination schedule,” Dr. Vázquez explained. Pertussis protection through maternal vaccination is not long lasting. Therefore, infants need to begin their DTaP vaccine series when they are two months old.
Additional Ways to Protect Infants
Dr. Vázquez mentioned that there are many ways to help protect against respiratory infections during pregnancy. “It is safe and recommended that pregnant woman get vaccinated against whooping cough, flu, COVID-19, and respiratory syncytial virus (RSV),” she continued. RSV can be especially dangerous as it is the leading cause of hospitalization among infants. There are two options to help protect infants from severe RSV illness. One option is an RSV vaccine given during weeks 32-36 of pregnancy in September through January. The other option is an RSV preventive antibody given to infants under 8 months in October through March. Dr. Vázquez adds that it’s safe for an individual to receive both the Tdap and RSV vaccines during pregnancy.
With pertussis on the rise again, the protective value of vaccination has never been clearer, especially for infants. Ensuring that Tdap and other recommended vaccines are received during each pregnancy, maintaining the childhood immunization schedule, practicing good hygiene (like washing hands often and covering coughs and sneezes)and encouraging others to talk to their healthcare provider about how to keep up today date on recommended vaccinations helps rebuild community-level protection and safeguard babies too young to be fully vaccinated themselves.
Blog last updated: December 18, 2025
